Immunostaining and cytometry analyses of SSEA-3 and SSEA-4 antigens. A) Photomicrographs of immunostaining of feline amniotic epithelial cells (AECs). Cells labeled with antibodies against antigen SSEA-4. Magnification 20×, scale bar = 20 mm. B) Flow cytometry analysis of SSEA-3 and SSEA-4 antigen expression with Alexafluor-488 labeled antibodies. Histograms represent relative number of cells vs. fluorescence intensity (FL1). Black histograms indicate background fluorescence intensity of cells labeled with isotype control antibodies only; gray histograms show positivity to the studied antibodies.